Zotac GeForce GTX 660 Ti Amp! Extreme Review

When Nvidia's GeForce GTX 660 Ti 2GB first launched four months ago, one of the partner cards we looked at was Zotac's amp! Edition, which featured fairly hefty overclocks to the core and memory speeds and was a solid card as a result. However, at £270, it was priced a little to closely to the superior GTX 670 2GB for our liking. We were therefore a little surprised (and pleased) to see the amp! Extreme edition retailing for £250, especially given that it features an even higher overclock.

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The GTX 660 Ti 2GB GPU is very similar to that of the GTX 670 2GB. Both cards feature the same 28nm GK104 Kepler GPU of the GTX 680 2GB, but with a single streaming multiprocessor disabled. This means that both GPUs house 1,344 stream processors and 112 texture units, as well as four rasterisers and seven tesselation units.

The difference between the GTX 660 Ti 2GB and the costlier GTX 670 2GB is found in the memory interface, as the cheaper card has three 64-bit memory controllers as opposed to four. Thus, its memory interface has been reduced from 256-bit to 192-bit, and its active ROP count is 24 instead of 32. Thanks to support for mixed density memory modules, however, the GTX 660 Ti still features 2GB of GDDR5 memory, with one of its controllers serving 1GB of this instead of the usual 512MB.

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The reference clock speeds of the GTX 660 Ti are 915MHz on the core and 1.5GHz (6GHz effective) for the memory. The Zotac amp! card that we looked at before featured an overclocked core clock speed of 1,033MHz as well as speedier memory at 1.65GHz (6.6GHz effective).

This 10 per cent increase in memory frequency has been maintained for the Extreme edition, giving the card 158.4GB/s of memory bandwidth. On the other hand, the core has been bumped up even further to 1,098MHz, which gives the card a boost clock of 1,176MHz (although it capped out at 1,254MHz in our testing) and represents a huge 20 per cent boost from reference speeds.

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That's essentially the only difference between the Extreme edition and the regular amp! card, as physically they're identical. The card features the same 180mm PCB and the same dual fan, dual slot orange and black cooler, the housing for which takes the total length of the card to 193mm. The copper baseplate cools the GPU, and transfers heat via three heat pipes to the fin stack. Sadly, most of the hot air resulting from the dual 80mm down-draft fans is exhausted back into your case.

Video outputs include one DVI-D, a DVI-I, an HDMI connection and a single DisplayPort, and the card sports two SLI connections for multi-GPU arrangements. Despite the increased overclock, power circuitry is the same as before. Two 6-pin PCI-E connections keep the card going, with four power phases for the GPU and two for the memory, giving the card 6+1 phase power.

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Due to the disabled memory controller, the font of the PCB appears to be missing two of its 256MB hynix memory chips. They can be found on the rear, however, stacked behind the pair with which they share a memory controller. The memory chips are not directly cooled, but as before, the VRMs are covered by their own heatsink near the rear I/O ports.